The present invention describes extra-cellular bacterial products from a marine bacteria, Alteromonas sp, name as Ni1LEM, deposited at the Agricultural Research Culture Collection under the Accession No NRRL B-30784. Said extracts are useful for inhibiting the settlement and fixing of marine benthic microalgea (diatomeae), marine macroalgae and marine invertebrate larvae, mainly those that are involved on problems known as “biofouling”, in the marine environment. Additionally, the present invention discloses the method for obtaining these extracts, which have biocide properties.
A surface, submerged on a marine ecosystem, is sensitive to be rapidly colonized. Said phenomenon is named “biofouling” or “bio-incrustation”, which corresponds to the undesired accumulation of microorganisms, algae and animals on surfaces or structures submerged in the sea; in a first moment said phenomenon is initiated, by the origin of a film containing organic matter and dissolved macromolecules, such as polysaccharides, proteins and protein fragments, followed by bacteria, microalgae, protozoan, algae and invertebrates. Those organisms constituting the “biofouling” can be divided in “micro-biofouling” and “macro-biofouling”. The micro-fouling or microbial films begin the colonization process on the exposed surfaces, after which occurs the colonization by the organisms that are responsible of the macro-biofouling (tunicates, balanides, mollusks and algae). Nevertheless, biofouling not only can be found non animated objects, but they can colonize the surface of marine plants and invertebrates. Some research studies have shown that the development of the biofouling on surfaces of non animated structures differs from the one of the colonized organisms, moreover the structures and constituents of the biofouling differ among one and other organism. However, at the sea, the marine algae and invertebrates are the main colonizers.
Substantial problems, to the structures submerged in the sea, are caused by the presence of “biofouling”, resulting in economical loss. Among the main problems caused by “biofouling” on the marine environments, are those related to aquaculture and marine structure systems, such as the petroleum platform columns and boat hulls. Therefore, in aquaculture, per example, the accumulation of “biofouling” on the nets of the cages used for the fish culturing in aquaculture, provokes the sinking of the same, as well as the reduction of the water flux through the mesh, causing a drastic decrease of the concentration, within this culture systems, of the dissolved oxygen. Similar problems occur with those culture systems used in the filter feeding mollusks (scallops, oysters and mussels), wherein the organisms that are being cultured compete with the “biofouling” organisms for oxygen and nutrients. The above, generates the need of periodically removing the culture systems from the sea into the land for cleaning the same. This maintenance of the culturing material represents a high cost for the aquaculture companies. The problem of the “biofouling” phenomenon is not only restricted to the sea aquaculture systems, therefore this is the way how the land systems are not free of the problems caused by “biofouling”. Per example, the tubes used for distributing the sea water for hatcheries of marine invertebrate's larvae and seed, of commercial importance, suffer the biologic colonization on their inner part, thus reducing the necessary pumping rate and the water flux.
For combating “biofouling” in marine structures, diverse toxic compounds have been used, being the most efficient, those compounds preferably based in tri-butyltin (TBT) or copper. These paints containing TBT are highly effective in the control of the biofouling in ships, achieving periods of seven years without requiring maintenance. Nevertheless, the environmental control policies have restricted the use of paints containing TBT in marine environments for crafts of more than 25 m of length, and due to its deleterious effects over the environment; the use of TBT should be eradicated on 2008. These rules are based on numerous studies about the effects of TBT, which have reported toxic effects, with so low concentrations, on marine organisms as mollusks.
One alternative for the paints containing TBT, are those in which the main constituent is copper and other heavy metals such as zinc. These paints are mainly used on small crafts, being effective during a period from 1 to 2 years. Nevertheless, government entities from several countries have indicated the risks of using these paints on the environment and the risk for the man, suggesting its prohibition. In this way, the International Maritime Organization has prohibited the use of tin in anti-biofouling paints from 2003 on. The use of copper in anti-biofouling paints is under a similar classification, being prohibited its use on the Baltic Sea from 2002 on. Copper, is toxic over some algae species and it is accumulated by those filter-feeding mollusks. It has been reported that a third part of the copper ions emission, on the north coast waters of Norway, come from anti-biofouling agents, used on aquaculture cages, a third part comes from the anti-biofouling paints used on craft hulls and the remaining third part from other sources. Nowadays, on Norway, the rules for the emission of these substances will produce a dramatic decrease of the emissions of these substances: the new net cleansing companies will have to adapt themselves to the new law from January of 2001, the old companies will have a period term for adapting themselves until 2005. These restrictions and limitations, have caused billionaire losses in the international shipping industry, resulting in an urgent necessity of manufacturing effective “anti-biofouling” technologies for replacing those paints containing toxic heavy metals and which would not exhibit environmental risks for the human health.
On the other hand, there are some products that use the nature as the source of the chemicals, which can be used both in anti-biofouling paints as in plastics, however, although nowadays some of them are in the market, there still is necessary more research on this subject, since many are the substances which have a potential use in preventing biofouling. The major part of these research projects or products are based in the fact that, many sessile aquatic organisms are free of biofouling, since they exhibit natural mechanisms as the production of metabolites with anti-fouling properties, at the level of affording protection against the colonization, reducing the competitiveness for the space in competitive environments. Also there are bacteria, mainly those of the Pseudoalteromona genus, which produce high molecular weigh substances with toxic and inhibitory properties for gram positive and gram negative bacteria. Until today, the bacterial specie Pseudoalteromona tunicate, has been widely studied regarding the production of a variety of extra-cellular components, which are responsible of inhibiting the settlement of common organisms of biofouling, such as bacteria, fungus, benthic microalgae, algae spores and marine invertebrates.
Some research projects developed for FONDEF (Fondo de Fomento al Desarrollo Científico y Tecnológico: Funds for the Promotion of the Scientific and Technologic Development) in our laboratory have allowed to isolate and identify a marine bacteria named as Ni1 LEM, which corresponds to an Alteromonas sp, which on laboratory in vitro studies and on the subsequent in situ studies, on the marine environment have shown the ability of significantly diminishing the settlement and fixing percentage, of the main components of the “biofouling” without affecting the culture organisms of commercial importance, further of being harmless for the environment.